The refrigeration cycle has numerous uses including refrigeration and freezing, air conditioning, and removing water from moist air to dehumidify air or to produce water.
During operation refrigeration evaporator coils of a refrigeration system tend to collect frost. As the frost grows, the airflow through the evaporator is reduced which reduces the effectiveness and efficiency of the refrigeration. For example, when evaporators on refrigerator storage systems freeze the interior air temperature of the system rises, possibly degrading or spoiling the product within. As the evaporator continues to collect water vapor the frost becomes hard ice, which can take hours to defrost. Such systems must be deiced, either manually or automatically, preferably before sufficient frost or ice has formed to cause a reduction in performance.
Present systems are generally defrosted by means of timers which turn the system off and/or use electrical heaters or hot gas to defrost the evaporator coils. Typical refrigeration systems have no means to “know” if they need to be defrosted or if defrosting is complete. Furthermore, many of the defrost systems currently available require a significant amount of power to complete, and the commercial refrigeration industry is responsible for the consumption of a large part of the world's power budget.
What is needed is a means to allow refrigeration or freezer systems to operate at any ambient air temperature, limit frost build up, while providing an effective, reliable means to defrost them without degrading the product within. The system described herein will accomplish these requirements.